The present invention relates to new and useful improvements in lifting systems, such as deep well pump systems, for moving a commodity from a first location to a second location at a higher elevation than the first location. More particularly, the present invention is concerned with a unique pump system wherein a sub-surface pump is controlled from a ground surface power unit through the use of hydraulic pressure, avoiding the necessity of mechanical pump rods and the like.
Specifically, the system proposed herein in illustrated embodiments involves the utilization of a sub-surface pump unit incorporating a collapsible volume chamber, the collapse of which is resisted by resiliently compressible means, or spring means, therein; either a compressible inert gas such as nitrogen or a mechanical spring. The resistance to collapsing developed by the spring means is essentially equal to the pressure developed by the height of the fluid column plus the desired discharge pressure whereby the pump unit is, without the application of pumping pressure from the surface power unit, maintained at full discharge condition. The power unit is adapted to contain two volumes, each generally equal to the volume of the collapsible volume chamber within the pump unit. A discharge of one volume from the power unit through the fluid column to the pump unit effects a full charging stroke of the pump piston by a full collapsing of the collapsible volume chamber so as to accommodate the introduced single volume from the power unit and a corresponding introduction of a second volume, from the well, into the working chamber above the pump piston through the linear movement thereof induced by the collapse of the collapsible volume chamber. Continued movement of the power unit subsequent to discharge of the first volume, through the increased pressure, opens an exhaust valve for a discharge of the second volume from the power unit into fluid storage facilities. The return stroke of the power unit piston releases the pressure on the exhaust valve so as to close the flow to fluid storage and causes a reduction of pressure on the fluid column and within the pump unit itself so as to enable, through the action of the spring means associated with the collapsible chamber, expanding the collapsible chamber and effect a simultaneous linear return of the pump or working piston so as to discharge the accumulated two volumes from the pump unit back into the power unit.
The system as above described basically involves a relationship whereby any force applied on the fluid column over and above the discharge pressure is transferred by the fluid column to the charging chamber, causing a collapse in volume of the collapsible volume chamber associated therewith a proportionate volumetric amount. This, in turn, is converted to linear travel of the pump piston in the working cylinder. When the force above the discharge pressure is released, the system returns to its essentially balanced condition and discharges the amount of additional fluid displaced within the working cylinder. As a normal situation, to be set forth in more detail subsequently, the system contemplates the introduction of one volume from the power unit to the pump unit at a developed pressure of twice the discharge pressure so as to effect a return flow of two volumes at the discharge pressure, thus providing a highly efficient operating system utilizing practical, readily available and economical components in the accommodation of wells of substantial depth, up to 15,000 or more feet. In connection therewith, as noted supra, the spring means or a compressible gas such as nitrogen in the deeper wells, can serve as the counterbalance means described later hereinafter. Also, the valving in the present invention is much simplified over that in similar prior art for greater economy, efficiency and less maintenance.
The inventor is aware of the following prior art U.S. Pat. Nos. 736,062; 1,616,773; 2,058,455; 2,917,000; 3,015,280; 3,109,379.
Additional features, objects and advantages of the invention which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed. Reference is had to the accompanying drawings forming a part hereof wherein like numerals refer to like parts throughout.